Productivity and Product Quality Measures for Chippers and Grinders on Operational Southern US Timber Harvests

Abstract

Growth in bioenergy interests in the southeastern United States has created a need for cost-effective woody biomass harvesting systems. We evaluated three operational systems for their potential production and cost: horizontal grinders fed with residue from roundwood harvests, horizontal grinders fed with residue from clean chipping harvests, and whole tree chippers fed with entire stems. We evaluated three contractors operating each of the three system types over the course of approximately one working week each. Utilization rates for chippers and grinders were 44% and 38% respectively. Hourly production ranged between 22 – 30 metric green tonnes (gt)/SMH and 64 – 70 gt/PMH and did not differ significantly between the three systems. Delivered costs per gt of material were also very similar for the three systems and ranged between $22.68 and $23.81.

Keywords:

• wood biomass
• chips
• harvesting
• logging costs